CommonNetFuncs.Images 4.1.14

CommonNetFuncs.Images

This project contains helper methods for dealing with base64 image encoding and image optimization.

Contents

• CommonNetFuncs.Images
  • Contents
  • Base64
    • Base64 Usage Examples
      • ConvertImageFileToBase64
      • CleanImageValue [Obsolete, please use ExtractBase64]
      • ExtractBase64
      • ImageSaveToFile
      • IsValidBase64Image
  • Manipulation
  • Manipulation Usage Examples - ResizeImage - ResizeTo Helpers - ConvertImageFormat - ReduceImageQuality - TryDetectImageType - TryGetMetadata
  • Fingerprinting
    • Fingerprinting Usage Examples
      • FingerprintImage
      • FingerprintDirectory
      • Compare and FindDuplicates
  • Optimizer
    • Optimizer Usage Examples
      • OptimizeImage
  • Installation
  • License

Base64

Helper methods for dealing with Base64 image encoding.

Base64 Usage Examples

<details> <summary><h3>Usage Examples</h3></summary>

ConvertImageFileToBase64

Converts an image file or stream to a Base64 string.

string base64String = ConvertImageFileToBase64(@"C:\path\to\image.jpg"); // Returns the Base64 string representation of the image file.

CleanImageValue [Obsolete, please use ExtractBase64]

Attempts to clean a Base64 string by removing any metadata or unwanted characters that may come with it when reading from an HTML element.

string base64String = "data:image/png;base64, iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==";
string? cleanedBase64 = CleanImageValue(base64String); // "iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg=="

ExtractBase64

Attempts to clean a CSS background image containing a Base64 string by removing any metadata or unwanted characters that may come with it when reading from an HTML element. Validates that the Base64 string is a valid image format.

string base64String = "data:image/png;base64, iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==";
string? cleanedBase64 = base64String.ExtractBase64(); // "iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg=="

ImageSaveToFile

Save a Base64 string to an image file.

string base64String = "iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==";
ImageSaveToFile(base64String, @"C:\path\to\output_image.png"); // Saves the Base64 string as an image file at the specified path.

IsValidBase64Image

Checks to see if a Base64 string is a valid image format.

string base64String = "iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==";
bool isValid = IsValidBase64Image(base64String); // true

</details>

Manipulation

Helper methods for manipulating images, such as resizing, and changing image quality.

Manipulation Usage Examples

<details> <summary><h3>Usage Examples</h3></summary>

ResizeImage

Resizes an image to the specified width and height, maintaining the aspect ratio if desired.

await ResizeImage(@"C:\path\to\input_image.jpg", @"C:\path\to\output_image.jpg", 800, 600); // "C:\path\to\output_image.jpg" contains the 800px x 600px resized image.

ResizeTo Helpers

Use lightweight helper overloads when you just need a resized SKBitmap (and optionally encoded output).

using FileStream input = File.OpenRead(@"C:\path\to\input_image.jpg");
using MemoryStream output = new();

// Stream -> SKBitmap
using SKBitmap resizedA = input.ResizeTo(320, 240);

// Stream -> SKBitmap + encoded output stream
using SKBitmap resizedB = input.ResizeTo(output, 320, 240, SKEncodedImageFormat.Jpeg, 90);

// SKBitmap -> resized SKBitmap
using SKBitmap sourceBitmap = SKBitmap.Decode(@"C:\path\to\input_image.jpg");
using SKBitmap resizedC = sourceBitmap.ResizeTo(320, 240);

// SKImage -> resized SKBitmap
using SKImage sourceImage = SKImage.FromBitmap(sourceBitmap);
using SKBitmap resizedD = sourceImage.ResizeTo(320, 240);

ConvertImageFormat

Converts an image from one format to another (e.g., JPEG to PNG).

await ConvertImageFormat(@"C:\path\to\input_image.jpg", @"C:\path\to\output_image.png", SKEncodedImageFormat.Png); // "C:\path\to\output_image.png" contains the converted image in png format.

ReduceImageQuality

Reduces the quality of an image by applying a specified JPEG quality level, which can help in reducing file size. Neither input nor output are required to be JPEG format.

await ReduceImageQuality(@"C:\path\to\input_image.jpg", @"C:\path\to\output_image.jpg", 50); // "C:\path\to\output_image.jpg" contains the image with reduced 50% quality

TryDetectImageType

Detects the image format of a file based on its content, returning the format as a string.

TryDetectImageType(@"C:\path\to\input_image.jpg", out SKEncodedImageFormat? format); // Returns true and format is Jpeg.

TryGetMetadata

Attempts to retrieve ImageMetadata from an image file.

TryGetMetadata(@"C:\path\to\input_image.jpg", out ImageInfo metadata); // Returns ImageInfo with properties like Width, Height, and EncodedFormat.

</details>

Fingerprinting

Helper methods for perceptual image fingerprinting and duplicate detection using AverageHash, DifferenceHash, and PerceptualHash.

Fingerprinting Usage Examples

<details> <summary><h3>Usage Examples</h3></summary>

FingerprintImage

Fingerprint a single file path.

ImageFingerprint fp = await @"C:\path\to\image.jpg".FingerprintImage(ImageHashAlgorithm.DifferenceHash);
// fp.Hash contains the 64-bit perceptual hash value

FingerprintDirectory

Fingerprint all supported images in a directory.

IReadOnlyList<ImageFingerprint> fingerprints = await ImageFingerprinting.FingerprintDirectory(
	@"C:\path\to\images",
	recursive: true,
	algorithm: ImageHashAlgorithm.PerceptualHash
);

Compare and FindDuplicates

Compare two fingerprints or scan a set for duplicates.

SimilarityResult pair = ImageFingerprinting.Compare(fingerprints[0], fingerprints[1], duplicateThreshold: 90.0m);

IReadOnlyList<SimilarityResult> duplicates = ImageFingerprinting.FindDuplicates(fingerprints, duplicateThreshold: 90.0m);

IReadOnlyList<SimilarityResult> duplicatesFromDirectory = await ImageFingerprinting.FindDuplicatesInDirectory(
	@"C:\path\to\images",
	recursive: true,
	algorithm: ImageHashAlgorithm.DifferenceHash
);

</details>

Optimizer

Helper methods for optimizing images.

Optimizer Usage Examples

<details> <summary><h3>Usage Examples</h3></summary>

OptimizeImage

Optimizes an image by reducing its file size without sacrificing quality using gifsicle, jpegoptim, or optipng CLI tools depending on the image format.

await OptimizeImage(@"C:\path\to\input_image.jpg", @"C:\path\to\output_image.jpg"); // "C:\path\to\output_image.jpg" contains the optimized image.

</details>

Installation

Install via NuGet:

dotnet add package CommonNetFuncs.Images

License

This project is licensed under the MIT License - see the LICENSE file for details.